Question: Can the hub part, CY7C66113 be used as a dual device (2 keyboard for example) hub connected to a host. Is this possible without the need for a hardware "wedge" circuit or a special driver?
No. The only way that this device allows for two implementations is as a Hub + function, no Function + Function is allowed.
USB does allow for multiple keyboards (in Windows, potential problems in Mac platform with multiple keyboards) You would need Two micro's, one to implement each keyboard and USB would take care of noticing the two keyboards seperately on the Host side.